Question: what are particles made out of?

Protons and neutrons are made up of three of a type of particle known as “quarks”. A proton is two “ups” and one “down”, and a neutron is one “up” and two “downs”. There are four other types of quark (strange, charm, bottom, top) but they have no relevance to everyday. It is believed that these are not made up of anything smaller.

Electrons are also thought not to be made up of anything smaller. (They have cousins – the muon and the tau lepton – that also aren’t relevant to everyday).

Our best understanding is the idea that Matthew laid out. These are the kinds of things that the Large Hadron Collider is investigating. It’s already found the Higgs Boson, which is what gives all the particles their mass, so who knows what else it might find?